During Rapid Serial Visual Presentation, readers can read sans-serif type about 20% faster at very small sizes. This advantage disappears at larger sizes. The study was done with fonts specially designed to control typeface parameters other than the serifs. The results suggest that rendering serifs at small sizes may be counterproductive.

We compared reading speed with two fonts, Dutch (serif) and Swiss (sans serif). Text was displayed on a computer monitor, white letters on black, with the RSVP method. Luminance of the letters was either 146.0 or 0.146 cd m-2. Lower-case x-height of the fonts was approximately 5.5 times as large as letter acuity. At the high luminance, there was no difference between reading rates. There was a significant advantage for the Swiss font at the low luminance. The acuity reserve for Swiss was higher than for Dutch at the low luminance, which may account for the difference in reading speeds.

Normally sighted younger and elder subjects as well as subjects with central visual field loss (CFL) from age-related maculopathy read rapid serial visual presentation (RSVP) text with words presented at a constant rate and at three different rates where word presentation duration varied according to word length. The elder subjects reading sentences foveally read fastest when word duration was constant. The younger group reading random words peripherally read faster at a variable word duration rate. The subjects with CFL read sentences an average of 33% faster when the presentation rate varied with word length. There was a trend for slow readers with CFL to benefit more than fast readers with CFL. We conclude that varying word duration based on word length in rapid serial visual presentation reading would improve reading rates for low-vision patients with CFL.

Miles A. Tinker defined legibility as the perception of letters, words and continuous text for reading: “The shapes of letters must be discriminated, the characteristic word forms perceived, and continuous text read accurately, rapidly, easily, and with understanding. In the final analysis, one wants to know what typographical factors foster ease and speed of reading” (Tinker, 1963).